Abstract: The paper aims to propose a watermarking algorithm based on rotation stable region and two-level SVD decomposition to improve the imperceptibility and the robustness of watermarking systems. First, the stable region where pixels are approximately lossless is selected. Then, the region is transformed by using redundant discrete wavelet transform, and the low-frequency sub-block is divided into non-overlapping blocks. Next, each subblock is decomposed by using SVD, and the first row and the first column of singular values are extracted to construct a characteristic matrix, and the characteristic matrix is decomposed by using SVD for the second time. Finally, an appropriate scaling factor is selected to embed the watermarking into the singular values of the characteristic matrix. When extracting watermarking, Radon transform is used to correct the host image containing the watermarking information, and the watermarking information is extracted. Experiments with the proposed algorithm show high PSNR values of above 45 dB and high normalized correlation (NC) values of greater than 0.90. It is verified that the watermarking algorithm performs good imperceptibility and ability of anti-geometric attack and highly guaranteed embedding capacity of the watermark. The algorithm has high practical application value in digital copyright protection.

Key words: rotational stable region, two-stage singular value decomposition, Radon correction, robustness, anti-rotation attack